The twin sons of Baltimore couple Amelia and John Eckhardt, Robert and John Jr., were born on August 27, 1911. Twenty minutes after the delivery of Robert, John Jr. appeared, to the horror of his parents and his midwife, who is said to have cried, "A broken doll!" It wasn't a clean break though - rather than appearing "snapped off at the waist" as he would later claim, little Johnny was left with withered, useless legs that never grew even as the rest of him did. Clothed as he always was in a neat tuxedo jacket, however, Johnny appeared to be a perfect half-man.

Robert was charged with looking after his brother, who was handicapped in name only - Johnny taught himself to walk on his hands at the age when most children learn to walk on their feet. Both twins were bright boys who excelled in school, and John aspired to be a preacher. At the age of thirteen, however, Johnny's career as the "King of Freaks" was already taking shape. The twins were spotted by a magician while attending a local carnival, who convinced them to join the sideshow, with Johnny working as a freak and Robert as his manager.

John loved everything about showbusiness. In the circus, he did acrobatics with his extraordinarily strong arms, trained animals, juggled, and played the front end of the magician's "sawed in half" illusion. When not performing as a circus freak, he and Robert conducted their own Baltimore-based orchestra. Johnny also drew and painted, and drove a custom-built race car, the "Johnny Eck Special".

Johnny Eck's most memorable appearance is in the movie Freaks, but he also had uncredited roles in three Tarzan movies. After these Hollywood appearances, the Eckhardt brothers went into semi-retirement in Baltimore, running a kiddie train ride in a local park. John also made a living with his paintings.

The event that turned Johnny from a beloved local celebrity into a sullen old recluse was a robbery at the family home, which he and Robert inhabited, in 1987. Old and enfeebled, Johnny was unable to defend himself as a gang of thieves physically restrained him and walked off with his valuables. It was this incident that is said to have inspired his famous quote, "If I want to see freaks, I can just look out the window," indicating that the once-congenial King of Freaks had finally lost faith in his fellow man. On January 5, 1991, after almost four years of living in total seclusion, Johnny suffered a heart attack and died. Robert followed him in 1995, aged 83.

The Eckhardt twins may be gone, but they are not forgotten, especially in their hometown of Baltimore. Jeffrey Pratt Gordon, the owner of their home on North Milton Avenue, has retained many of their possessions, including the miniature train Johnny drove, and has put together an amazing website, The Johnny Eck Museum with the intent of sharing the twins' incredible story with the world.